You choose both the aperture and the shutter speed. Manual mode even offers a shutter speed of "bulb" for long exposures. Because you control both aperture and shutter speed, manual mode offers great scope for expression. But choose the wrong combination and your photo will be too bright or too dark, or in other words over- or under-exposed. Keep your eye on the exposure indicator when choosing aperture and shutter speed.
01. Rotate the mode dial to M.
02. Checking the exposure indicato, adjust shutter speed and aperture. Shutter
Shutter speed is selected by rotating the command dial (right for faster speeds, left for slower).
03. To adjust aperture, keep the Adjusting Aperture button pressed while rotating the command dial (left for larger apertures/lower f-numbers and right for smaller apertures/higher f-numbers).
View information on functions related to Exposure Mode: Manual (Mode M).